Relationship Between Strength Parameters and Functional Performance Tests in Patients With Severe Knee Osteoarthritis.

BACKGROUND: Decreased leg muscle strength is a major determinant of reduced function in patients with knee osteoarthritis (OA). The identification of a strength parameter that is best correlated with functional performance is important for monitoring rehabilitation results. OBJECTIVE: To determine which muscle strength measurements show the highest correlation with functional capacity in patients with severe knee OA shortly before total knee arthroplasty (TKA). DESIGN: Cross-sectional exploratory study. SETTING: Outpatient rehabilitation department at a university teaching hospital. PATIENTS: The sample included 75 patients (51 female) scheduled for primary TKA, recruited through multistage sampling. METHODS OR INTERVENTIONS: Independent variables were peak isometric, isokinetic concentric, and eccentric leg extensor strength measured on the leg press, as well as peak isometric knee extensor strength measured on the strength chair. Two multiple regression analyses were performed, one including all strength measures and the other including all of the strength ratios. Pearson correlation coefficients were calculated between the strength measures and functional test scores. MAIN OUTCOME MEASUREMENTS: Dependent variables were the Timed Up and Go Test (TUG) and the Stair Test (ST). RESULTS: The regression analysis including all strength measures could explain 11.9% of the variance of the TUG (P = .068, not significant [NS]) and 21.5% of the variance of the ST (P = .009, significant). The regression model for the strength ratios explained 11.8% of the variance of the TUG (P = .090, NS) and 6.3% of the ST (P = .217, NS). CONCLUSIONS: Although univariate analysis confirmed significant correlations between strength measurements and functional tests, multiple regression analysis revealed a higher predictive value for the ST than for the TUG. The use of both muscle strength tests and performance-based function tests is advisable to evaluate functional impairments of patients with knee OA. LEVEL OF EVIDENCE: III.

Effects of Leg-Press Training With Moderate Vibration on Muscle Strength, Pain, and Function After Total Knee Arthroplasty: A Randomized Controlled Trial.

OBJECTIVES: To examine the effects of a time-saving leg-press training program with moderate vibration on strength parameters, pain, and functional outcomes of patients after total knee arthroplasty (TKA) in comparison with functional physiotherapy. DESIGN: Randomized controlled trial. SETTING: Outpatient rehabilitation department at a university teaching hospital. PARTICIPANTS: Patients (N=55) with TKA were randomly allocated into 2 rehabilitation groups. INTERVENTIONS: Six weeks after TKA, participants either underwent isokinetic leg-press training combined with moderate vibration (n=26) of 15 minutes per session or functional physiotherapy (n=29) of 30 minutes per session. Both groups received therapy twice a week for a period of 6 weeks. Participants were evaluated at baseline (6wk after TKA) and after the 6-week rehabilitation program. MAIN OUTCOME MEASURES: The main outcome measure was maximal voluntary contraction (MVC) of the involved leg. Secondary outcome measures were pain assessed with a visual analog scale (VAS), range of motion, stair test, timed Up and Go test, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). RESULTS: Both groups showed statistically significant improvements in MVC of knee extensors measured on the knee dynamometer (leg-press group: from 0.8±.06 to 1±.09Nm/kg body weight [BW], physiotherapy group: from 0.7±.06 to 0.9±.06Nm/kg BW; P<.05) and in closed kinetic chain on the leg press (leg-press group: from 8.9±.77 to 10.3±1.06N/kg BW, physiotherapy group: from 6.7±.54 to 9.1±.70N/kg BW; P<.05) and in pain at rest (leg-press group: from 2±.36 to 1.3±.36 on the VAS, physiotherapy group: from 1.2±.28 to 1.1±.31; P<.05), WOMAC scores, and functional measurements after 6 weeks of training. There was no significant difference between the 2 groups concerning strength, pain, and functional outcomes after training (P>.05). CONCLUSIONS: Isokinetic leg-press training with moderate vibration and functional physiotherapy are both effective in regaining muscle strength and function after TKA; however, isokinetic leg-press training is considerably less time consuming.

Vascular function in obese children with non-alcoholic fatty liver disease.

OBJECTIVE: To test whether obese children with non-alcoholic fatty liver disease have impaired vascular function compared with obese children with normal liver fat content. METHODS: Obese children (n = 28, 16 males, mean age 10.9 ± 0.7 years, body mass index [BMI] 31.9 ± 4.5 kg/m(2)) with normal (HCLn) and increased hepatocellular lipid content (HCLi, 2.6 ± 0.8 vs. 12.4 ± 8.2%) were recruited, outcome measures being flow-mediated dilation of the brachial artery [FMD] measured by ultrasound, biochemical markers of inflammation (hs-CRP, hs-IL6) and cell adhesion molecules [CAMs], hepatocellular lipids, visceral and subcutaneous fat quantified by nuclear magnetic resonance spectroscopy and imaging. RESULTS: HCLi and HCLn groups showed no significant differences in terms of age, gender, BMI, waist circumference and subcutaneous fat. Subjects in the HCLi group had significantly higher amounts of visceral fat and higher fasting glucose, insulin and triglyceride, but lower adiponectin levels and were more insulin resistant than their HCLn controls. Hepatic fat fraction (HFF) correlated positively with fasting plasma glucose, HOMA-IR, adiponectin, visceral fat, negatively with WBISI independent of BMI. HFF was not associated with subcutaneous fat, fasting insulin, FFA, HDL-C, TG, hs-CRP, hs-IL6, vCAM, iCAM, and FMD. HCLi patients had significantly higher serum levels of hs-CRP and hs-IL6 than HCLn controls. FMD and serum levels of vCAM and iCAM were comparable between groups. CONCLUSIONS: Obese children with simple steatosis rather than steatohepatitis seem to have intact vascular function. Further studies in obese children with different grades of NAFLD are warranted to elucidate the role of fatty liver as a marker of risk for future cardiovascular events.